Method and apparatus for transmitting uplink control information in multi-carrier wireless communication system

ABSTRACT

A method and apparatus are provided for transmitting Uplink Control Information (UCI) on a data channel in a multi-carrier wireless communication system. The method includes channel-coding a UCI with reference to a number of UCI bits available; dividing the channel coded UCI bits into a number of Physical Uplink Shared Channels (PUSCHs); and transmitting the UCI multiplexed with data on the individual PUSCHs.

PRIORITY

This application is a continuation application of U.S. patentapplication Ser. No. 13/144,403, which was filed in the U.S. Patent andTrademark Office on Jul. 13, 2011, as National Stage Entry ofPCT/KR2010/000206, and claims priority to Korean Application Serial No.10-2009-0002808, which was filed in the Korean Intellectual PropertyOffice on Jan. 13, 2009, the entire content of each of which isincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a multi-carrier wireless communicationsystem and, in particular, to a method and apparatus for transmittinguplink control information on data channels in a wireless communicationsystem supporting multicarrier transmission.

2. Description of the Related Art

Recently, Orthogonal Frequency Division Multiplexing (OFDM) is appliedto most broadcast and wireless communication systems. OFDM isadvantageous for wireless communication because of the robustness to themultipath fading channel, guaranteeing orthogonality between multipleaccess users, and spectrum efficiency. Due to these advantages, OFDM isconsidered as one of the most attractive transmission techniques forhigh speed and broadband communication system and even superior to theDirect Sequence-Code Divisional Multiple Access (DS-CDMA) technique.However, the high peak to average power ratio (PAPR) of the OFDMincreases the power consumption, and this may decrease the coverage. Forthis reason, the 3GPP Long Term Evolution (LTE) uses the OFDM for thedownlink and Single Carrier Frequency Division Multiple Access (SC-FDMA)for uplink to increase the coverage and reduce the power consumption ofthe mobile terminal. Since both the OFDM and SC-FDMA are multiplexingthe users or channels in frequency domain, there is similarity inallocating frequency resources as the scheduling resources.

FIG. 1 is a diagram illustrating a structured of a subframe carryingUplink Control Information (UCI) in the conventional LTE system, andFIG. 2 is a diagram illustrating a structure of a subframe carrying theUCI and data in the conventional LTE system.

The UCI includes the Acknowledgement/Negative-Acknowledgement (ACK/NACK)information related to data packet received in the downlink, ChannelQuality Indicator (CQI) reports, and Rank Indicator (RI) information,and is transmitted on a Physical Uplink Control Channel (PUCCH). Asshown in FIG. 1, the PUCCH 101 and 102 is transmitted on reservedfrequency regions at the edges of the total available bandwidth in theuplink. In this case, when the mobile terminal transmits the packetdata, the reserved frequency region cannot be used for PUCCH. This isbecause the simultaneous transmission of the PUCCH for the UCI and thePhysical Uplink Shared Channel (PUSCH) for the data does not fulfill thesingle carrier characteristic and thus increases the PAPR.

In the current LTE system, the UCI is transmitted on the frequencyresource allocated for the data, i.e. PUSCH, in the duration fortransmitting the uplink data as shown in FIG. 2. In case of transmittingthe UCI on the PUSCH resource, the multiplexing scheme is changeddepending on the characteristic of the control information. That is, theCQI information is rate-matched, attached at the tail of data bits, andmapped to physical bits, thereby arranged at a rear position 107 of thesubframe; and the ACK/NACK information is arranged at positions 106where the data bits are punctured at both sides of the reference symbol.The RI information is arranged at both sides of the reference symbol asthe ACK/NACK information between the data bits rather than puncturingthe data bits. Since some parts of the resource allocated for the datatransmission are used regardless of the transmission scheme, the datatransmission amount is reduced as much as the resource used fortransmitting the UCI.

How the resource amount for transmitting the UCI, when transmitting theUCI along with the data on the PUCCH resource, is described hereinafter.

Here, the resource means a number of symbols or a number of bitsallocated for the PUSCH.

In case of transmitting the UCI on the PUCCH, the information bits arechannel-coded such that the number of bits to be transmitted on thePUCCH is fixed per type of UCI. By increasing or decreasing thetransmission power, the receipt quality can be maintained at a targetlevel. In case of transmitting the UCI with the data on the PUSCH, thetransmission power for the UCI should be equal to that for the data. Ifthe data are transmitted in high spectral efficiency or high Modulationor at high Coding Scheme (MCS) level, the received Signal to Noise Ratio(SNR) per symbol increases; and otherwise, if the data are transmittedin low spectral efficiency or low MCS level, the received SNR per symboldecreases. In order to maintain the reception quality of the UCI, anumber of transmission symbols for the UCI is needed to be adjusted inconsideration of the data. In LTE, the number of transmission symbolsrequired for the UCI is adjusted according to the spectral efficiency ofthe data transmitted on the PUSCH. This can be expressed by an equation.When the number of symbols available for transmitting the UCI is Q′, Q′can be obtained using an equation. The number of symbols fortransmitting the ACK/NACK or RI information is calculated as equation(1):

$\begin{matrix}{Q^{\prime} = {\min\left( {\left\lceil \frac{O \cdot M_{sc}^{PUSCH} \cdot N_{symb}^{PUSCH} \cdot \beta_{offset}^{PUSCH}}{\sum\limits_{r = 0}^{C - 1}K_{r}} \right\rceil,{4 \cdot M_{sc}^{{PUSCH}\text{-}{current}}}} \right)}} & (1)\end{matrix}$

where O denotes a number of bits of the ACK/NACK information or RankIndicator (RI) information, M_(sc) ^(PUSCH) denotes a number ofsubcarriers allocated for the transmission of PUSCH, N_(symb) ^(PUSCH)denotes a number of SC-FDMA symbols for transmitting PUSCH, and Kr is anumber of data bits before channel coding. All these parameters areobtained from the PDCCH received at the initial transmission. β_(offset)^(PUSCH) denotes an offset value for taking into consideration of thedifference between target SNRs of the data and UCI.

Given a number of symbols, a number of bits to be channel-coded of eachUCI can be obtained by equation (2) in consideration of the modulationscheme.

Q _(ACK) =Q _(m) ·Q′  (2)

where Q_(m) is a value indicating the modulation scheme (set to ‘2’ forQPSK and ‘4’ for 16QAM).

The equation for the CQI information is similar to that for the ACK/NACKinformation and RI basically. However, since a Cyclic Redundancy Check(CRC) can be added for the CQI large in size and the RI is alwaysassigned the resource, the equation is modified for the remainedresource to fulfill the minimum resource amount for the CQI informationas equation (3):

$\begin{matrix}{Q^{\prime} = {\min \begin{pmatrix}{\left\lceil \frac{\left( {O + L} \right) \cdot M_{sc}^{PUSCH} \cdot N_{symb}^{PUSCH} \cdot \beta_{offset}^{PUSCH}}{\sum\limits_{r = 0}^{C - 1}K_{r}} \right\rceil,} \\{{M_{sc}^{{PUSCH}\text{-}{current}} \cdot N_{symb}^{{PUSCH}\text{-}{current}}} - \frac{Q_{RI}}{Q_{m}}}\end{pmatrix}}} & (3)\end{matrix}$

where L denotes a number of CRC bits that are not inserted when O isequal to or less than 11 bits but inserted when O is greater than 11bits, thereby being defined by

$L = \left\{ {{\begin{matrix}0 & {O \leq 11} \\8 & {otherwise}\end{matrix}.M_{sc}^{{PUSCH}\text{-}{current}}} \cdot N_{symb}^{{PUSCH}\text{-}{current}}} \right.$

means numbers of subcarriers and SC-FDMA symbols constituting thesubframe. Q_(RI) denotes a number of bits for the RI information. Giventhe number of symbols, the number of CQI bits after channel codingaccording to the modulation scheme used for the CQI is calculated asequation (4):

Q _(CQI) =Q _(m) ·Q′  (4)

A multi-carrier transmission principle for the LTE-Advanced (LTE-A) isdescribed hereinafter. In the current LTE system, a cell transmitsmultiple subcarriers on a single carrier, and the mobile terminal alsotransmits on a single carrier. In the LTE-A system, however, multiplecarriers can be aggregated to increase the maximum transmission rate soas to provide spectral efficiency. Nevertheless, the respective carriersmaintained in LTE structure to support legacy LTE terminals, and thesecarriers are called Component Carriers and aggregated to extend theentire bandwidth.

FIG. 3 is a diagram illustrating a principle of carrier aggregation inthe LTE-A system. In FIG. 3, four Component Carriers are depictedexemplarily. Each of the four Component Carriers 201, 202, 203, and 204has the reserved region at the edges for the PUCCH 205 and 206 and thedata regions for the PDCCH region at the center.

Accordingly, there is a need for a method for a terminal to transmit theUCI and data simultaneously in the wireless communication systemsupporting the carrier aggregation. That is, although the LTE-A systemuses the PUSCH resource for the transmission of the UCI and data as inthe LTE system, there is a need to consider how to assign the resourcefor the UCI to support the carrier aggregation where the PUSCH isassigned multiple component carriers. There is therefor a need to definehow to multiplex the UCI into multiple PUSCH resource, i.e. how manyPUSCH symbols to be assigned for the UCI transmission.

SUMMARY OF THE INVENTION

In order to solve the above problems of prior arts, an aspect of thepresent invention is to provide a method for transmitting uplink controlinformation along with data in a multicarrier communication systemsupporting carrier aggregation.

Since the LTE-A system supports allocation of PUSCH on multiplecarriers, there is a need to define how to multiplex the UCI on themultiple carriers, i.e. how many number of PUSCH symbols to be assignedfor the UCI transmission. Another aspect of the present invention, is toprovide a method and apparatus for transmitting the UCI and dataefficiently in an LTE-A system by introducing an algorithm that iscapable of selecting the carrier to be used, calculating the PUSCHresource amount for transmitting the UCI on the PUSCH of thecorresponding carrier, and multiplexing the UCI and data.

In accordance with an aspect of the present invention, a method isprovided for transmitting the UCI in a wireless communication systemsupporting multicarrier transmission. The method includes channel-codinga UCI with reference to a number of UCI bits available; dividing thechannel coded UCI bits into a number of PUSCHs; and transmitting the UCImultiplexed with data on the individual PUSCHs.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certainembodiments of the present invention will be more apparent from thefollowing detailed description in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a diagram illustrating a structured of a subframe carryingUplink Control Information (UCI) in the conventional LTE system;

FIG. 2 is a diagram illustrating a structure of a subframe carrying theUCI and data in the conventional LTE system;

FIG. 3 is a diagram illustrating a principle of carrier aggregation inthe LTE-A system;

FIG. 4 is a diagram illustrating aggregation of component carrierstransmitting PUCCHs carrying the UCI according to the first embodimentof the present invention;

FIG. 5 is a diagram illustrating aggregation of component carrierstransmitting PUSCHs carrying the UCI and data according to the firstembodiment of the present invention;

FIG. 6 is a flowchart illustrating a method for a mobile terminal totransmit a UCI in a wireless communication system according to a firstembodiment of the present invention;

FIG. 7 is a flowchart illustrating a method for a base station toreceive the UCI in a wireless communication system according to a firstembodiment of the present invention;

FIG. 8 is a block diagram illustrating a configuration of a mobileterminal for performing the UCI transmission method of FIG. 6;

FIG. 9 is a block diagram illustrating a configuration of a base stationfor performing the UCI reception method of FIG. 7;

FIG. 10 is a diagram illustrating aggregation of component carrierstransmitting PUCCHs carrying the UCI according to the second embodimentof the present invention;

FIG. 11 is a diagram illustrating aggregation of component carrierstransmitting PUSCHs carrying the UCI and data according to the secondembodiment of the present invention;

FIG. 12 is a flowchart illustrating a method for a mobile terminal totransmit a UCI in a wireless communication system according to a secondembodiment of the present invention;

FIG. 13 is a flowchart illustrating a method for a base station toreceive the UCI in a wireless communication system according to a secondembodiment of the present invention;

FIG. 14 is a block diagram illustrating a configuration a mobileterminal for performing the UCI transmission method of FIG. 12;

FIG. 15 is a block diagram illustrating a configuration of a basestation for performing the UCI reception method of FIG. 13; and

FIG. 16 is a graph illustrating typical performance degradation as thecode rate increases in a system using a turbo code.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Exemplary embodiments of the present invention are described withreference to the accompanying drawings in detail. The same referencenumbers are used throughout the drawings to refer to the same or likeparts. Detailed descriptions of well-known functions and structuresincorporated herein may be omitted to avoid obscuring the subject matterof the present invention. The terms and words used in the followingdescription and claims are not limited to the bibliographical meanings,but, are merely used by the inventor to enable a clear and consistentunderstanding of the invention. Accordingly, it should be apparent tothose skilled in the art that the following description of exemplaryembodiments of the present invention are provided for illustrationpurpose only and not for the purpose of limiting the invention asdefined by the appended claims and their equivalents.

The present invention provides a method for transmitting uplink data andcontrol information simultaneously and efficiently in a wirelesscommunication system supporting multicarrier transmission. That is, thepresent invention provides a method and apparatus for a mobile terminalto transmit the UCI along with the data in a LTE-A system supportingcarrier aggregation. In case of simultaneous transmission of the dataand UCI, the UCI is carried on the PUSCH resources of multiple componentcarriers. The present invention provides a method for assigning theresources for transmitting the UCI in carrier aggregation mode. The UCItransmission method of the present invention is capable of improving UCIreliability without compromising the data transmission performance. Theexemplary embodiments of the UCI transmission method of the presentinvention are described hereinafter.

In the UCI transmission method for a wireless communication systemsupporting carrier aggregation according to a first exemplary embodimentof the present invention, the transmitter divides the UCI into segmentsand multiplexes the UCI segments into a number of PUSCHs such that theUCI segments are transmitted with the data simultaneously, and thereceiver demultiplexes the UCI segments from the multiple PUSCHs intothe original UCI.

In the UCI transmission method for a wireless communication systemsupporting carrier aggregation according to a second exemplaryembodiment of the present invention, the transmitter transmits the UCIon the PUSCH resource of one of multiple aggregated carriers, and thereceiver extracts the UCI from the PUSCH resource of the correspondingcarrier.

First Embodiment

In the first embodiment of the present invention, when a subframecarries the UCI and data simultaneously, the UCI is segmented intomultiple pieces and then transmitted on the multiple PUSCHs in adistributed manner.

FIG. 4 is a diagram illustrating aggregation of component carrierstransmitting PUCCHs carrying the UCI according to the first embodimentof the present invention, and FIG. 5 is a diagram illustratingaggregation of component carriers transmitting PUSCHs carrying the UCIand data according to the first embodiment of the present invention.

Referring to FIG. 4, the UCI is transmitted on the PUCCHs since theuplink resource has not assigned to the mobile terminal yet. Forinstance, a plurality of CQI informations or HARQ ACK/RI informationsare transmitted on the PUCCHs as denoted by reference numerals 305, 306,and 307 as shown in FIG. 4. However, when the uplink resource has beenassigned, the UCI is transmitted on the PUSCHs along with the uplinkdata as denoted by reference numerals 314, 316, and 318 of FIG. 5. Incase that the UCI is transmitted on the PUSCH, the UCI is distributed onthe entire PUSCHs, thereby increasing frequency diversity gain.

How to calculate the resource amount per PUSCH for transmitting the UCIis described hereinafter. When a number of bits of the UCI to betransmitted on the k^(th) PUSCH is Q_k, the Q_k is calculated byequations (5) and (6):

$\begin{matrix}{\mspace{20mu} {{{Q\_ k} = {Q_{m,k} \cdot {\min \begin{pmatrix}{{{p\_ k} \cdot \left\lceil \frac{o_{k} \cdot M_{{sc},k}^{PUSCH} \cdot N_{{symb},k}^{PUSCH} \cdot \beta_{{offset},k}^{PUSCH}}{\sum\limits_{r = 0}^{C - 1}K_{r,k}} \right\rceil},} \\{4 \cdot M_{{sc},k}^{{PUSCH}\text{-}{current}}}\end{pmatrix}}}},}} & (5) \\{{Q\_ k} = {Q_{m,k} \cdot {\min \begin{pmatrix}{{{p\_ k} \cdot \left\lceil \frac{\left( {O + L} \right) \cdot M_{{sc},k}^{PUSCH} \cdot N_{{symb},k}^{PUSCH} \cdot \beta_{{offset},k}^{PUSCH}}{\sum\limits_{r = 0}^{C - 1}K_{r,k}} \right\rceil},} \\{{M_{{sc},k}^{{PUSCH}\text{-}{current}} \cdot N_{symb}^{{PUSCH}\text{-}{current}}} - \frac{Q_{{RI},k}}{Q_{m,k}}}\end{pmatrix}}}} & (6)\end{matrix}$

where O denotes a number of information bits of the UCI, M_(sc,k)^(PUSCH) is a number of subcarriers assigned for k^(th) PUSCH,N_(symb,k) ^(PUSCH) is a number of SC-FDMA symbols of k^(th) PUSCH, andK_(r,k) is a number of data bits before the channel coding per codeblock at k^(th) PUSCH. Q_(m,k) is a value determined according to themodulation scheme (2 for QPSK and 4 for 16QAM).

Unlike the LTE system, the LTE-A system uses a newly introducedparameter p_k which determine the amount of the UCI bits per PUSCH. Inan exemplary embodiment of the present invention, p_k is defined withtwo different methods in order to minimize the influence to the PUSCHtransmission.

In the first method, the number of UCI symbols to be carried by eachPUSCH is determined at the rate of physical bits that can be transmittedon each PUSCH. The first method for calculating the p_k can be expressedas equation (7):

$\begin{matrix}{{p\_ k} = \frac{M_{{sc},k}^{{PUSCH}\text{-}{current}} \cdot N_{{symb},k}^{{PUSCH}\text{-}{current}} \cdot Q_{m,k}}{\sum\limits_{k = 0}^{s}{M_{{sc},k}^{{PUSCH}\text{-}{current}} \cdot N_{{symb},k}^{{PUSCH}\text{-}{current}} \cdot Q_{m,k}}}} & (7)\end{matrix}$

where M_(sc) ^(PUSCH-current)·N_(symb) ^(PUSCH-current)·Q_(m,k) denotesa number of the subcarriers, a number of SC-FDMA symbols, and modulationscheme per PUSCH in a subframe.

In the second method, the number of UCI symbols to be carried by eachPUSCH is determined at the rate of the modulation symbols on each PUSCHresource. The second method for calculating the p_k can be expressed asequation (8):

$\begin{matrix}{{p\_ k} = \frac{M_{{sc},k}^{{PUSCH}\text{-}{current}} \cdot N_{{symb},k}^{{PUSCH}\text{-}{current}}}{\sum\limits_{k = 0}^{s}{M_{{sc},k}^{{PUSCH}\text{-}{current}} \cdot N_{{symb},k}^{{PUSCH}\text{-}{current}}}}} & (8)\end{matrix}$

If the number of symbols required for transmitting the UCI per PUSCH iscalculated by the above methods, it is advantageous to distribute thequality degradation of the data transmission uniformly. This isdescribed with an exemplary case. Let's assume that two carriers areassigned for the PUSCH as shown in table 1.

TABLE 1 Modulation # of # of # of Code (Qm) symbols coded bitsInformation bit rate PUSCH 2 150 300 100 0.33 1 PUSCH 4 400 160 10000.625 2

If the CQI information to be transmitted is O=20 bits, Q′ for each PUSCHis obtained by equation (3) after calculating the p_k using the firstand second methods. Here, it is assumed that the number of subcarriersand the number of SC-FDMA symbols allocated by an initial PDCCH areidentical with the number of subcarriers and the number of SC-FDMAsymbols in the current subframe to be transmitted, respectively.

TABLE 2 Q′ actual Difference p_k (symbol) code rate in code rate UniformPUSCH 1 0.5 15 0.37 0.037 division PUSCH 2 0.5 4 0.63 0.006 Method 1PUSCH 1 0.35 5 0.34 0.011 PUSCH 2 0.65 7 0.64 0.011 Method 2 PUSCH 10.27 8 0.35 0.019 PUSCH 2 0.73 6 0.63 0.010

When Q′ symbols are used for transmitting the UCI information, thenumber of symbols for transmitting the data decreases such that theactual code rate increases as shown in 5^(th) column of table 2. The6^(th) column of table 2 shows the difference between the actual coderate and the ideal code rate when no UCI information is transmitted onthe PUSCH. If the base station performs scheduling without considerationof the UCI transmission, the data transmission performance of the PUSCHis deteriorated as the code rate difference increases. The first methoddivides the number of UCI symbols at the physical bit rate such that thevariation of the code rate is uniform accurately. When the UCIinformation are allocated to the two PUSCH uniformly without using anyof the first and second methods, the variation of the code rate of datain PUSCH 1 is very high and, as a consequence, the data transmissionperformance of the PUSCH 1 is highly degraded. In case of using thefirst method, the number of UCI symbols are divided at the physical rateand thus the variation of the code rates are identical in both the PUSCH1 and PUSCH 2. In case of using the second method, the variation of coderate is high in the PUSCH using low level modulation scheme due to thelarge puncturing amount. This is to make the performance degradationuniform by allocating relatively large number of symbols to the QPSKmodulated symbols and relatively small number of symbols to the 16QAMmodulated symbols since the performance degradation caused by the coderage change is greater in 16QAM than in QPSK as shown in FIG. 16. FIG.16 is a graph illustrating typical performance degradation as the coderate increases in a system using a turbo code.

In the third method, the UCI bits are allocated to each PUSCH inproportion to the spectral efficiency and the number of symbols of theallocated PUSCH resource. The third method is similar to the secondmethod except for considering the spectral efficiency such that thePUSCH resource having high spectral efficiency is preferably used toreduce the quality degradation of the PUSCH.

$\begin{matrix}{{p\_ k} = \frac{\left( {M_{{sc},k}^{{PUSCH}\text{-}{current}} \cdot N_{{symb},k}^{{PUSCH}\text{-}{current}}} \right)^{2}/\left( {\sum\limits_{r = 0}^{C - 1}K_{r,k}} \right)}{\sum\limits_{k = 0}^{s}{\left( {M_{{sc},k}^{{PUSCH}\text{-}{current}} \cdot N_{{symb},k}^{{PUSCH}\text{-}{current}}} \right)^{2}/\left( {\sum\limits_{r = 0}^{C - 1}K_{r,k}} \right)}}} & (9)\end{matrix}$

The total number of bits for transmitting one UCI is the sum of the UCIbits of individual PUSCHs and can be defined as

${Q = {\sum\limits_{k = 0}^{s}{Q\_ k}}},$

where s is the number of scheduled PUSCHs.

FIG. 6 is a flowchart illustrating a method for a mobile terminal totransmit a UCI in a wireless communication system according to a firstembodiment of the present invention.

Referring to FIG. 6, the mobile terminal detects a need to transmit aUCI (401) and determines whether the PUSCHs have been allocated in thecorresponding subframe for transmitting data (402). If no PUSCH has beenallocated, the mobile terminal transmits the UCI on the preset PUCCH(403). Otherwise, if the PUSCHs have been allocated, the mobile terminalcalculates a Q_k per PUSCH (404). At this time, the mobile terminalcalculates the Q_k using equations (5) and (6). Next, the mobileterminal sums up the Q_k values of individual PUSCHs to obtain Q andperforms channel coding by using the Q value (405) and divides thechannel-coded UCI at the rate of Q_k per PUSCH (406). Next, the mobileterminal multiplexes the data and UCI per PUSCH (i.e., multiplexes thedata and UCI per carrier) (407). At this time, the CQI information isarranged after the data as in the LTE system, the ACK/NACK informationis substituted for corresponding data bits, and the RI informationinserting at corresponding position by shifting the data bits. Aftermultiplexing the UCI and data, the mobile terminal transmits the PUSCHs(408).

FIG. 7 is a flowchart illustrating a method for a base station toreceive the UCI in a wireless communication system according to a firstembodiment of the present invention.

Referring to FIG. 7, the base station detects a receipt of the UCItransmitted by a mobile terminal (501) and determines whether the PUSCHhas been allocated to the mobile terminal in the corresponding subframe(502). If no PUSCH has been allocated to the mobile terminal, the basestation receives the UCI on the preset PUCCH (507). Otherwise, if thePUSCH has been allocated to the mobile terminal, the base stationcalculates the Q_k values of individual PUSCHs (503). At this time, theQ_k values are calculated using equations (5) and (6). Next, the basestation extracts the coded UCI bits as much as Q_k per PUSCH (504) andthen performs channel decoding on the entire coded bits (505).

FIG. 8 is a block diagram illustrating a configuration of a mobileterminal for performing the UCI transmission method of FIG. 6.

As shown in FIG. 8, the mobile terminal includes a plurality of channelcoders 603 and 604, a plurality of dividers 605 and 606, a UCItransmission controller 615, and a plurality of PUSCH transmission units615 and 616. The first per carrier transmitter 615 includes amultiplexer 609, an interleaver 611, and a PUSCH transmitter 613. TheM^(th) PUSCH transmission unit 616 includes a multiplexer 610, aninterleaver 612, and a PUSCH transmitter 614.

The channel coder 603 (or 604) is responsible for channel coding perUCI. Here, the ACK/NACK information and RI information are channel codedby the same channel coder. In FIG. 8, the channel coder 604 performschannel coding on the ACK/NACK information or RI information, and thechannel coder 603 performs channel coding on the CQI information. Theinput of the channel coders 603 and 604 is the UCI information havingthe length of 0, and the output of the channel coders 603 and 604 arechannel-coded bits having the length of Q. Q is the sum of the Q_kvalues of the individual PUSCHs. The channel coders 603 and 604 outputthe channel-coded bits, i.e. the coded UCI, to the correspondingdividers 605 and 606. The UCI controller 615 controls the channel coders603 and 604 and the dividers 605 and 606 and calculates and outputs theQ_k value per UCI and total Q value to the dividers 605 and 606.

The PUSCH transmission units 615 and 616 receive the outputs of thedivider 605 and 606 and data packets and multiplex the divided codedUCIs and data. The number of PUSCH transmission units is determineddepending on the number of allocated PUSCHs. In the exemplary embodimentof FIG. 8, it is assumed that M PUSCHs are allocated for datatransmission. Each PUSCH transmission unit includes the multiplexer,interleaver, and PUSCH transmitter. The multiplexers 609 and 610 insertthe UCI at the tail of the data rate-matched as much as the data amountto be transmitted after encoding. At this time, the multiplexers 609 and610 multiplex the data and the CQI information output by the divider 605as shown in FIG. 8. The ACK/NACK information or RI information input tothe interleavers 611 and 612 so as to be interleaved with the output ofthe multiplexers 609 and 610. That is, the CQI is multiplexed with thedata, and then interleaved with the multiplexed data and ACK/NACKinformation or RI information at the interleavers 611 and 612. Themultiplexed data and UCI are processed by the PUSCH transmitters 613 and614 and then transmitted through the PUSCH channels.

As aforementioned, the PUSCH transmission units 615 and 616 are providedas many as the number of PUSCHs and distribute the UCI on the individualPUSCHs to transmit along with the packet data. Here, the divider 605divides the CQI information and outputs the divided CQI information tothe multiplexers 609 and 610 in distributed manner, and the divider 606divides the ACK/NACK information or RI information and outputs thedivided ACK/NACK information or RI information to the interleavers 611and 612 in distributed manner. The multiplexers 609 and 610 multiplexesthe CQI information and the packet data, and the interleavers 611 and612 interleaves the outputs of the multiplexers 609 and 610 with theACK/NACK information or RI information and output the multiplexedresults to the PUSCH transmitters 613 and 614.

FIG. 9 is a block diagram illustrating a configuration of a base stationfor performing the UCI reception method of FIG. 7.

As shown in FIG. 8, the base station includes a plurality of channeldecoders 703 and 704, a plurality of combiners 705 and 706, a pluralityof PUSCH reception units 715 and 716, and a UCI reception controller717. The first PUSCH reception unit 715 includes a demultiplexer 709, adeinterleaver 711, and a PUSCH receiver 713, and the M^(th) PUSCHreception unit 716 includes a demultiplexer 710, a deinterleaver 712,and a PUSCH receiver 714.

The number of PUSCH reception units is determined depending on thenumber of allocated PUSCHs. Each of the PUSCH reception unit 715 and 716includes a PUSCH receiver, a deinterleaver, and a demultiplexer. ThePUSCH receivers 713 and 714 receives the data an UCI transmitted by themobile terminal on the PUSCHs. The UCI reception controller 717 outputsQack 1, . . . , Qack M values representing the amounts of coded UCI ofthe ACK/NACK information or the RI information for the individual PUSCHsto the deinterleaver 711 and 712 to calculate the amount of the ACK/NACKinformation and RI information, and outputs the Qcqi 1, . . . Qcqi Mvalues representing the amount of the coded UCI for individual PUSCHs tothe demultiplexers 709 and 710 to calculated the amount of the CQIinformation.

In case that the UCI is transmitted, the deinterleavers 711 and 712performs deinterleaving on the PUSCHs to output the multiplexed data andACK/NACK information and/or RI information. In order to calculate theamounts of the ACK/NACK information and RI information, thedeinterleavers 711 and 712 uses the Qack_(—)1, . . . , Qack_M valuesrepresenting the coded UCI amounts on the individual PUSCHs carrying theACK/NACK information or the RI information. The CQI information isextracted by the demultiplexers 709 and 710. In order to extract the CQIinformation, the demultiplexers 709 and 710 use the Qcqi_(—)1, . . . ,Qcqi_M values provided by the UCI reception controller 717.

The UCI bits extracted from the individual PUSCHs are output to thecombiners 705 and 706 so as to be combined into coded UCIs. The codedUCIs are output to the channel decoder 703 and 704 so as to be decodedinto the original UCI.

Second Embodiment

In the second embodiment of the present invention, when multiple PUSCHsare allocated in multiple carriers for data transmission, one of thePUSCH resources (called special PUSCH) is used for transmission of theUCI.

FIG. 10 is a diagram illustrating aggregation of component carrierstransmitting PUCCHs carrying the UCI according to the second embodimentof the present invention, and FIG. 11 is a diagram illustratingaggregation of component carriers transmitting PUSCHs carrying the UCIand data according to the second embodiment of the present invention.

Referring to FIG. 10, 4 component carriers 806, 807, 808, and 809 areaggregated, and the UCI is transmitted on the PUCCHs since the uplinkresource has not assigned to the mobile terminal yet. The PUCCHs aretransmitted on the reserved regions at the edges 803, 804, and 805 ofthe component carriers. However, when the PUSCH has been assigned in thesubframe, the UCI 801 is multiplexed with the PUSCH 811 in a carriercomponent as shown in FIG. 11. In FIG. 11, the PUSCH are assigned in thefirst, second, and fourth carriers 817, 816, and 814, and the UCI iscarried on the PUSCH of the fourth carrier 814. This is because thePUSCH of the fourth carrier is the special PUSCH of the mobile terminal.

How to select a special PUSCH is described hereinafter.

The first method multiplexes the UCI with the data on the PUSCH assignedby a dynamic scheduling but not by the semi-persistent scheduling (PSP).Typically, the SPS resource is small in size and occurs periodically fortransmitting the delay sensitive data such as Voice over IP (VoIP)traffic. If the UCI transmission is carried on the SPS resourceallocated for the delay sensitive data transmission, the data may not becompletely transmitted at a time due to the puncturing loss caused bythe UCI. Since the delay sensitive data is vulnerable to retransmission,it is preferred not to use the SPS resource for transmitting the UCI.Accordingly, the PUSCH allocated on the dynamic scheduling resource isselected as the special PUSCH.

The second method multiplexes the UCI with the data on the PUSCH havingthe low spectral efficiency. As aforementioned in the first embodiment,as the spectral efficiency is low, the puncturing loss decreases.Accordingly, it is preferred to multiplex the UCI with the data on thePUSCH having the lowest spectral efficiency.

The third method multiplexes the UCI with the data on the PUSCH of thecarrier indicated by the lowest carrier index. This method is thesimplest method for selecting the special PUSCH to carry the UCI. Inthis case, the terminal-specific carrier indexing set by the upper layersignaling, rather than the cell-specific carry indexing, can be used.For instance, a UE1 can use the index list sorted in order of carrier 1,carrier 2, carrier 3, and carrier; while a UE2 uses the index sorted inorder of carrier 3, carrier 2, carrier 1, and carrier 4, whereby the UEshave the different lowest indices.

These methods can be used in combination with each other. For instance,when multiple carriers are allocated dynamic scheduling resources, thespecial PUSCH can be selected using the second and third methods,although it is possible to transmit the UCI on the multiple carriers indistributed manner as described in the first embodiment.

FIG. 12 is a flowchart illustrating a method for a mobile terminal totransmit a UCI in a wireless communication system according to a secondembodiment of the present invention.

Referring to FIG. 12, the mobile terminal detects a need to transmit aUCI (901) and determines whether the PUSCHs have been allocated in thecorresponding subframe for transmitting data (902). If no PUSCH has beenallocated, the mobile terminal transmits the UCI on the preset PUCCH(903). Otherwise, if the PUSCHs have been allocated, the mobile terminalselects a special PUSCH (904). The special PUSCH is selected by using atleast one of the first to third methods. In case that only one carrierassigned the PUSCH exist, the very PUSCH is selected as the specialPUSCH. Next, the mobile terminal calculates the Q value (905). The Qvalue is calculated using equations (1) to (4). Once the Q value iscalculated, the mobile terminal performs channel coding on the UCIaccording to the UCI type using the Q value (906). Next, the mobileterminal multiplexes the UCI and data on the special PUSCH (907) andtransmits the PUSCHs (908).

FIG. 13 is a flowchart illustrating a method for a base station toreceive the UCI in a wireless communication system according to a secondembodiment of the present invention.

Referring to FIG. 13, the base station detects a receipt of the UCI ofthe UCI transmitted by a mobile terminal (1001) and determines whetherthe PUSCH has been allocated to the mobile terminal in the correspondingsubframe (1002). If no PUSCH has been allocated to the mobile terminal,the base station receives the UCI on the present PUCCH (1003).Otherwise, in the PUSCH has been allocated to the mobile terminal, thebase station selects the special PUSCH (1004). The special PUSCH isselected by using at least one of the first to third methods as in themobile terminal. Next, the base station calculates the Q value usingequations (1) to (4), based on the information about the special PUSCHand the UCI (1005). Next, the base station extracts the UCI as much asthe Q from the special PUSCH (1006). Finally, the base station performschannel decoding on the extracted UCI (coded UCI bits) to obtain the UCI(1007).

FIG. 14 is a block diagram illustrating a configuration a mobileterminal for performing the UCI transmission method of FIG. 12.

As shown in FIG. 14, the mobile terminal includes a plurality of channelcoders 1101 and 1103, a UCI transmission controller 1103, a plurality ofswitches 1104 and 1105, a plurality of PUSCH transmission units 1111 and1112. The first PUSCH transmission 1111 includes a multiplexer 1106, aninterleaver 1108, and a PUSCH transmitter 1110; and the M^(th) PUSCHtransmission unit 1113 includes a multiplexer 1107, and interleaver1109, and a PUSCH transmitter 1112. The mobile terminal supports MPUSCHs.

The channel coders 1101 and 1102 perform channel coding on respectivetypes of UCI. The UCI transmission controller 1103 provides the channelcoders 1101 and 1102 with the length of the coded bits to be outputsince the number of the coded bits is changed depending to the spectralefficiency of the PUSCH. The UCI transmission controller 1103 selectsthe special PUSCH according to the above described process, determinesthe Q value according to the spectral efficiency of the special PUSCH,and outputs the Q value to the channel coder 1101 and 1102.

Each of the PUSCH transmission units 1111 and 1113 includes amultiplexer, an interleaver, and a PUSCH transmitter. The multiplexers1106 and 1107 multiplexes the CQI information of the UCI with the data,and the interleavers 1108 and 1109 interleavers the ACK/NACK informationor the RI information with the output of the multiplexers 1106 and 1107.In the second embodiment of the present invention, the UCI ismultiplexed with the data on only the special PUSCH, and thus theswitches 1104 and 1105 are needed. Once the special PUSCH is selected,the UCI transmission controller 1103 controls the switches 1104 and 1105to output the channel coded UCI only when the special PUSCH istransmitted. For instance, if it is determined to transmit the UCI onthe carrier 1 (i.e. the carrier 1 is selected as the special carrier),the switches 1104 and 1105 are switched to the PUSCH transmission unit1111 under the control of the UCI transmission controller 1103, wherebythe multiplexer 1106 multiplexes the CQI information of the UCI outputby the channel coder 1101 with the data to be transmitted on the specialPUSCH, and the interleaver 1108 interleaves the ACK/NACK information orthe RI information of the UCI output by the channel coder 1102 with theoutput of the multiplexer 1106. As a consequence, the PUSCH transmitter1110 of the PUSCH transmission 1111 transmits the data along with theUCI, and the PUSCH transmitter 1112 of the PUSCH transmission unit 1113transmits only data.

FIG. 15 is a block diagram illustrating a configuration of a basestation for performing the UCI reception method of FIG. 13.

As shown in FIG. 15, the base station includes a plurality of channeldecoders 1201 and 1202, a plurality of combiner 1203 and 1204, aplurality of PUSCH reception units 1212 and 1213, and a UCI receptioncontroller 1207. The first PUSCH reception unit 1212 includes ademultiplexer 1205, a deinterleaver 1208, and a PUSCH receiver 1210; andthe M^(th) PUSCH reception unit 1213 includes a demultiplexer 1206, adeinterleaver 1209, and a PUSCH receiver 1211.

The number of PUCCH reception units of the base station is determineddepending on the number of PUSCHs, i.e. the number of aggregatedcarriers. Each of the PUSCH reception units 1212 and 1213 includes aPUSCH receiver, a deinterleaver, and a demultiplexer. The demultiplexerperforms demultiplexing on the received signal to extract the CQIinformation, and the deinterleaver performs deinterleaving on thedemultiplexed signal to extract the ACK/NACK information or the RIinformation. The UCI reception controller 1207 calculates the Q valueand provides the calculated Q value to the PUSCH reception units 1212and 1213. At this time, the Q value is provided to the multiplexer anddeinterleaver of one of the PUSCH reception units 1212 and 1213 which isresponsible for processing the special PUSCH. That is, the UCI receptioncontroller 1207 checks the special PUSCH and provides the Q value to thePUSCH reception unit which is responsible for the special PUSCH.

As described above, the UCI transmission/reception method and apparatusof the present invention is capable of determining the resources fortransmitting the UCI on the PUSCHs in the system supporting multicarriertransmission efficiently, thereby improving reliability of the UCItransmitted on the PUSCHs without compromising data transmissionperformance of the PUSCHs.

Although exemplary embodiments of the present invention have beendescribed in detail hereinabove, it should be clearly understood thatmany variations and/or modifications of the basic inventive conceptsherein taught which may appear to those skilled in the present art willstill fall within the spirit and scope of the present invention, asdefined in the appended claims.

What is claimed is:
 1. An Uplink Control Information (UCI) transmissionmethod in a wireless communication system supporting multicarriertransmission, comprising: channel-coding a UCI with reference to anumber of UCI bits available; dividing the channel coded UCI bits into anumber of Physical Uplink Shared Channels (PUSCHs); and transmitting theUCI multiplexed with data on the individual PUSCHs.